Seal for centrifugal pumps



Feb. w, 1942. E. R. WILFLEY 2,272,454

SEAL FOR CENTRIFUGAL PUMPS Filed June 11, 1940 2 Sheets-Sheet 1 4 24 I /3 /5 22 Q: I 9 /6 INVENT OR. [AMER W/LFLfY Feb. H0, 1942. R, wlLFLEY ZQYZAEQ SEAL FOR CENTRIFUGAL PUMPS Filed June 11, 1940 2 Sheets-Sheet 2 INVENTOR. [LIVE P l?- W/LFL fy WM WM Patented Feb. 10, 1942 SEAL FOR CENTRIFUGAL PUMPS Elmer R. Wilfley, Denver, Colo., assignor to A. R.

Wilfley and Sons Inc., Denver, 6010., a corporation of Colorado Application June 11, 1940, Serial No. 339,920 '1 claims. (on. 28

This invention relates to improved sealing means for centrifugal pumps. More particularly, this is an improvement over the construction shown in United States Patent No. 1,976,532, issued to Elmer R. Wilfiey under date of October 9, 1934.

Centrifugal pumps have commonly been provided with stufling boxes around the shafts where they enter the casing. However, in pumping liquids containing abrasive materials, such as sand, or in pumping slurry, corrosive chemicals and the like, it has been found highly desirable to eliminate the stuffing box and to use instead, a centrifugally actuated seal around the shaft, which provides an opening entirely around the shaft during operation of the pump, but which automatically seals the shaft when the pump is not operating.

It is an object of the present invention to provide centrifugally actuated sealing means for a centrifugal pump, the actuating mechanism of which is completely separated from the pump casing by means of a rigid head for complete protection.

Another object is to provide such sealing means that seats with any back pressure that may exist in the pump, in contradistinction from seating against such pressure.

Other objects and advantages reside in details of design and construction which will be more fully disclosed in the following description and in the drawings wherein like parts have been similarly designated and in which:

Figure 1 is a fragmentary sectional view of a centrifugal pump which embodies a preferred form of this inventive concept;

Figure 2 is a fragmentary sectional view illustrating certain novel details of the structure illustrated in Figure 1 and drawn to a larger scale;

Figure 3 is a fragmentary sectional view of another type centrifugal pump in which is embodied a modified form of this invention; and

Figure 4 is a sectional view of the sealing element shown in Figures 1 and 2 and drawn to a larger scale. a

In order to illustrate reductions to practice of this invention, the accompanying drawings are made a part hereof and will be described in some particularity. However, these illustrations are intended to present typical examples and should not be construed to expressor to imply any limitation to the invention, the scope of which is, in reality, measured by the appended claims.

Referring first to Figure 1, reference character 55 5 denotes a pump case having an inlet through structure 6 and provided with a discharge outlet at I. A runner 8 is mounted upon a shaft 9 for rotation within the case 5. The shaft 9 is suitably journalled in the housing H) which is connected with the pump assembly by means of a short cylinder l2.

A sealing element I3 is mounted around the shaft 9, and in this example, this sealing element is a combination sleeve and flange made of rubher which may, if desired, be reinforced with fabric. This sealing element may be constructed of material other than rubber, but rubber has been found highly satisfactory. The sleeve portion of this sealing element has an annular fold I3a which enables the flange portion to move axially with reference to the shaft without moving the entire sealing element as a whole. The shaft 9 is not mounted for axial movement, as

has been the case in certain other patented struc-- ture pertaining to this art.

The flange portion of the sealing element it is attached to an axially movable cylindrical member 14, and this flange portion of the sealing element is in contact with a cooperating seat l5 when the pump is not in actual use.

A spring I6 urges the member M in a direction to draw the flange of the sealing member 53 securely against its seat I5, but when the shaft 9 is rotating, weights ll that are pivotally mounted on labyrinth collar 18, move outwardly, thus urging their respective fingers I9 against projections 20 on member M, to move the sealing element it away from its seat I5 and to provide a complete opening around the shaft 9. When rotation of the shaft 9 ceases, the spring I6 will act again to bring the sealing member l3 against its seat 45.

Any material being pumped that slips or leaks back through the opening around the shaft 9 during operation will pass into the interior |2a of the short cylinder l2 and thence through an opening 2! through the wall of said cylinder to the atmosphere.

A collar 22 is securely mounted upon the cylindrical member I4 for conjoint {rotation therewith and is provided with radial arms 23, thus tending to prevent accumulation of material within the short cylinder 12 by constantly acting upon it to prevent caking or clogging and tending to throw it toward and out of the opening 2|. It is manifest that sealing member l3, the cylindrical member H, the labyrinth collar I8, the centrifugal weights I1 and the cleaner collar 22 all rotate conjointly with the shaft 9. The element 22-43 best illustrated in Figure 2, may aptly be called a rotary scavenger.

A stationary head 33 extends from the interior of the short cylinder I 3 inwardiy to a close fit around the cylindrical member I3. This provides a rigid, stationary head or partition completely separating and protecting the centrifugal mechanism from contamination by the material being pumped.

This is an important advantage because sand or corrosive chemicals or the like, would seriously damage the centrifugal mechanism back of the head 33 if it were allowed to come in contact therewith.

As hereinbefore set forth, the spring i3 acts to move the sealing member l3 against its stationary seat I! when the rotation of the pump ceases and this seating of the seal is further and greatly facilitated by any back pressure that may be within the pump case. Such back pressure may be relatively high, due to a hydrostatic head in the standpipe that is ordinarily connected with the pump discharge. Threaded collar l3a provides a factor of adjustment for the compression of the spring l6.

Thus is provided a self-cleaning centrifugally actuated seal for a centrifugal pump which seats 7 with back pressure in the pump casing rather than against such pressure and whose precision centrifugal means are securely protected against damage from the material being pumped by a solid stationary head.

The preferred form of rubber sealing element i3 is illustrated in detail in Figure 4 and comprises a gasket-like flange portion l3b integrally connected with a shaft fitting sleeve portion i3c through the intermediary of a relatively thin wall section in which is the fold I3a. The inner end of the sleeve portion I3 is undercut back as at l3d, thus greatly facilitating the flexibility of the thin wall section and holding the overall axial length of the sealing element to a minimum. This arrangement. provides for movement of the flange or gasket-like portion D with reference to the sleeve portion i3a without disrupting the complete seal effected around the shaft by the sleeve portion.

Referring to Figure 3, the pump casing 33 is provided with an intake 3|, and a runner element 32 is mounted for rotation conjointly with a shaft 33. A labyrinth collar 34 supports centrifugal weights 35 that are pivotally mounted thereon for movement by centrifugal force. Each weight 35 is provided with a finger 33 which is positioned to contact an axially movable sleeve 31 which in turn abuts a sealing member 33 which is urged against a seat 33 by means of a compression spring acting through the intermediary ofaringll.

When the shaft 33, together with labyrinth collar 33 and th weights 33, rotate, said weights 35 will move outwardly under centrifugal force, thus urging the movable sleeve 31 toward the sealing member 33 to move it away from its seat 33 and open an annular passage leading from the interior of the Dump case 33 to the space immediately surrounding the shaft 33 which in turn is in communication with the atmosphere. when rotation ceases, the spring 33 will act to reseat the seal 33 on its seat 33 and this movement will be facilitated by any back pressure that may exist within the pump case. The inherent flexibility of the sealing member 33 permits movement of its sealing surface without its displacement as a whole.

The construction illustrated in Figure 3 is intended for use where the liquid being pumped is of a less damaging nature than the material that would ordinarily pass through the pump illustrated in Figures 1 and 2.

What I claim and desire to secure by Letters Patent is:

1. In a centrifugal pump having a rotor case and a shaft extending thereinto, an improved automatic sealing mechanism for the shaft comprising a rotary annular sealing element positioned around the shaft in sealed engagement therewith and having a radially extending flange that is axially movable by flexure with reference to said shaft, a stationary annular seat on the pump case positioned to cooperate with the flange of said sealing element, and means automatically actuated by rotation of said shaft and engaging the flange of said sealing element for pushing said flange away from the seat when the shaft rotates.

2. In a centrifugal pump having a rotor case and a shaft extending thereinto, an improved automatic sealing mechanism for the shaft comprising a rotary annular sealing element positioned around the shaft in sealed engagement therewith and having a radially extending flange that is axially movable by flexure with reference to said shaft, a stationary annular seat on the pump case positioned to cooperate with the flange of said sealing element, means automatically actuated by rotation of said shaft and associated with the flange of said sealing element for pushing said flange away from the seat when the shaft rotates, and resilient means for resisting such unseating movement.

3. In a centrifugal pump having a rotor case and a shaft extending thereinto, an improved automatic sealing mechanism for the shaft comprising a rotary annular sealing element positioned around the shaft in sealed engagement therewith and having a radially extending flange that is axially movable by flexure with reference to said shaft, a stationary annular seat on the pump case positioned to cooperate with the flange of said sealing element, means automatically actuated by rotation of the shaft and associated with the flange of said sealing element for pushing said flange away from the seat, a housing around said automatically actuated means, and a rotary scavenger carried on the shaft in said housin there being an opening in said housing for scavenger purposes.

4. In a centrifugal pump having a rotor case and a shaft extending thereinto' and a hubbed rotor on said shaft within said case, an improved automatic sealing mechanism for the shaft comprising a rotary annular sealing element positioned around the shaft in sealed engagement therewith and having a radially extending flange that is axially movable by flexure with reference to said shaft, a stationary annular seat on the pump case positioned to cooperate with the flange of said sealing element, means automatically actuated by rotation of the shaft and associated with the flange of said sealing element for pushing said flange toward said rotor and away from the seat, and resilient means carried on said rotor hub for resisting such unseating movement. v

5. In a centrifugal pump having a rotor case and a shaft extending thereinto, an improved automatic sealing mechanism for the shaft comprising arotary annular sealing element positioned around the shaft in sealed engagement therewith and having a radially extending flange that is axially movable by flexure with reference to said shaft, a stationary annular seat on the pump case positioned to cooperate with the flange of said sealing element, and means inclusive of pivotal centrifugal weights carried on said shaft and a sleeve around the shaft engaging the flange of the sealing element and associated with said centrifugal weights for relative.

to said shaft, a stationary annular seat on the a pump case positioned to cooperate with the flange of said sealing element, means inclusive of pivotal centrifugal weights carried on the shaft and a sleeve around said shaft engaging said flange and axially movable with reference to the shaft by said weights, for pushing said flange away from the seat when the shaft rotates, resilient means for resisting such unseating movement, a housing around said sleeve and centrifugal weights, and a rigid stationary head around said sleeve between said weights and the sealing element and extending radially to the inner surface of said housing.

,7. In a centrifugal pump having a rotor case and ashaft extending thereinto, an improved automatic sealing mechanism for the shaft comprising a rotary annular sealing element positioned around the, shaft in permanent sealed engagement therewith at least a part of which is axially movable by flexure with reference to said shaft, a stationary annular seat on the pump case positioned to cooperate with the movable part of said sealing element, and means automatically actuated by rotation of the shaft and engaging said movable part of said sealing element for pushing thesame away from the seat to break the pump seal whenever the shaft rotates, and a spring engaging said movable part of the seal tending to resist such movement and to reseat the seal upon the seat.

ELMER R. WILFLEY. 

